Automatically focus the ColorSchemeListView when we navigate to the ColorSchemes page

[PankajBhojwani]

Summary of the Pull Request

#11971 regressed when we implemented ColorSchemeViewModel in #13179. This commit fixes that by automatically focusing the ColorSchemeListView when we navigate to the ColorSchemes page, which makes sense from a user experience perspective anyway.

PR Checklist

• [ ] Closes #xxx
• [x] CLA signed. If not, go over here and sign the CLA
• [ ] Tests added/passed
• [ ] Documentation updated. If checked, please file a pull request on our docs repo and link it here: #xxx
• [ ] Schema updated.
• [x] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

Validation Steps Performed

Cannot repro #11971 anymore.